1. Field of the Invention
This invention relates to a bowling ball and more particularly to a bowling ball having a removable finger insert and to a method of changing the inner diameter of a finger hole in a bowling ball.
2. Description of the Prior Art
Bowling balls having means to change the inner diameter of the finger holes are well known in the art. For example, U.S. Pat. No. 2,314,811 discloses an apparatus for determining the relative position of the finger and thumb holes in a bowling ball and includes insert members adjustably secured within the bowling ball.
U.S. Pat. No. 2,435,327 discloses a bowling ball with a insert sleeve having a base portion that has wall engaging elements that are moved into frictional engagement by an adjustment screw. The insert member is thus secured within the bowling ball hole only at the base of the oversized finger hole formed in the ball. In one embodiment, the insert has an internally corrugated surface to facilitate frictional gripping of the ball.
U.S. Pat. No. 2,436,976 also discloses an insert with a radially expansive device to frictionally engage the wall of the oversized finger hole at the base of the insert.
U.S. Pat. No. 2,842,367 has an insert secured in an oversized finger hole that contains air inflatable chambers to change the inner diameter of the insert.
U.S. Pat. No. 2,950,111 discloses an arcuate semi-cylindrical pad that is arranged to move radially within the finger hole by an adjusting screw to change the inner diameter of a portion of the hole.
U.S. Pat. No. 3,004,762 discloses an insert with a longitudinal split and an external flange against which an adjusting screw positioned transverse to the split rotation of the adjusting screw reduces and increases the split in the insert to thus increase and decrease the diameter of the finger hole. The adjusting screw does not extend radially and would appear to unbalance the ball.
U.S. Pat. No. 3,012,783 has an adjustable finger insert which includes a cylindrical insert secured in the finger hole with an internal threaded portion and an inturned upper flange. An adjusting nut is threadedly secured in the cylindrical insert. A flexible sleeve abuts the nut and the inturned upper flange in the insert so that rotation of the nut flexes the flexible sleeve to change the inner diameter of the finger hole.
U.S. Pat. No. 3,416,796 discloses a cylindrical insert that is moveable within a cylindrical sleeve secured in the bowling ball finger hole. The sleeve has an inturned wall with an inward taper and the insert has an external wall with an outward taper. A bolt is secured to the insert bottom wall and is threaded into the bowling ball. Rotation of the bolt moves the insert relative to the cylindrical sleeve to increase or decrease the inner diameter of the insert.
U.S. Pat. No. 4,560,162 has a liner with an off center finger hole an a flexible insert positioned therein. A screw in the liner abuts a flange on the insert and adjusts the diameter of the flexible insert.
U.S. Pat. No. 4,561,654 discloses a pair of insert tubes threaded to each other for rotation relative to each other and a finger receiving flexible tube is secured to the inner threaded insert. The flexible tube has a wedge shaped outer surface so that the insert tubes when rotated relative to each other change the internal diameter of the finger receiving tubes.
Substantially all of the prior art disclose inserts that have one or more flexible tubes which are flexed or compressed to change the diameter of the finger hole. Screws or other adjusting means are required and it is a trial and error method of obtaining the desired inner diameter of the finger hole insert because of the flexibility and compressibility of the insert. The flexible inserts also have the disadvantage of being compressible and frequent adjustment is required to compensate for the resilience of the inserts.
There is a need for a rigid finger insert that may be tested for proper diameter and fit outside of the bowling ball and quickly placed in a bowling ball of the desired weight and spacing for the fingers.
In public bowling establishments, frequently bowlers who do not have their own ball will try many bowling balls that are on the return racks in an effort find a bowling ball that has the desired weight, the desired spacing of the finger and thumb holes and thumb and fingers of the desired inner diameter.
With this invention, it is now possible to select the appropriate bowling ball with the desired weight and then select a finger hole insert of the desired inner diameter to obtain an optimum fit for the thumb and the other fingers if desired.
This invention also provides a means for a bowler having his own bowling ball to quickly change the inner diameter of the finger hole insert when the thumb swells and expands or shrinks and contracts during bowling.
Bowling balls are provided with one or more finger holes and a thumb hole. These holes are arranged to receive the thumb and one or more fingers of the bowler. Throughout the specification, the description of the invention will be directed to a thumb hole which will be referred to as a finger hole and it should be understood that the invention is intended to encompass, where desired, the ability to change the diameter of one or more of the finger holes and the thumb holes in the bowling ball. The embodiments are intended to illustrate the invention and are not intended to limit the invention to the changing of the diameter of any single hole.